1. Field
One embodiment of the present invention relates to a telephone exchange system which employs computer telephony integration (CTI).
2. Description of the Related Art
An exchange network system, for example in an enterprise having a plurality of branch offices and business offices, installs a telephone exchange apparatus such as a private branch exchange (PBX) and a key telephone apparatus in each branch office and a business office, and connects these telephone exchange apparatuses with one another via exclusive lines. This kind of system may perform an inter-extension communication among different telephone exchange apparatuses and an office line transmission/reception via different telephone exchange apparatuses as well as may perform an inter-extension communication and an office line transmission/reception through a public network etc. for each telephone exchange apparatus.
By the way, also in the foregoing system, employment of the CTI has been examined. The CTI connects a personal computer to the telephone exchange apparatus, makes the personal computer perform a part of exchange processing of the telephone exchange apparatus, and store, process, etc., a voice and data, then may achieve a system with a high function without having to enhance the processing function of the telephone exchange apparatus.
However, the system given above needs to install a computer for CTI for every telephone exchange apparatus, it increases in cost of the whole of the system. Conventionally, a method in which the computer for the CTI is connected to one of the plurality of telephone exchanges to share the computer with a large number of telephone exchange apparatuses has been proposed (e.g., Jpn. Pat. Appln. KOKAI Publication 9-512690).
However, when a fault occurs on a telephone exchange apparatus to be a request side of an additional service by the computer for the CTI, the corresponding telephone terminal becomes disabled to utilize all additional services until the fault is recovered.